110 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



CONCLUSIONS. 



The results of experiments reported in the present paper corrobo- 

 rate those earlier obtained by the bureau (Bui. 80, Pt. VII, p. 146) as 

 to the efficiency of the one-spray method in controlling the codling 

 moth and plum curculio. Bringing together the results of all of the 

 tests which represent several seasons and varied conditions, it is 

 found that the average of the percentages of sound fruit from a 

 single spraying is 90.64 as compared with 96.19, the average of the 

 percentages of sound fruit on the demonstration plats receiving from 

 three to five applications. The unsprayed plats' show an average of 

 57.79 per cent of fruit free from codling-moth injury. The variation 

 in percentage of sound fruit is considerably greater with plats receiv- 

 ing the single application than where the demonstration treatment 

 was given, indicating, perhaps, a less degree of insurance from 

 injury, especially under unusual seasonal conditions, as in case of 

 injury of fruit by hail, etc., as occurred in Virginia during 1909. For 

 the entire period the range in percentage of sound fruit on the demon- 

 stration plat is from 92.91 (Michigan, 1911) to 99.42 (Virginia, 1910) 

 and on the one-spray the range is from 84.07 per cent (Virginia, 1909) 

 to 99.01 per cent (Virginia, 1910). 



In Prof. Gossard's work in Ohio (Bui. 191, Ohio Agr. Exp. Sta.) 

 a single spraying resulted in 91.60 per cent of sound fruit as 

 compared with 45.80 per cent from unsprayed trees. In West Vir- 

 ginia, Rumsey (Bui. 127, W. Va. Univ. Agr. Exp. Sta.) obtained by 

 the one-spray method 97.40 per cent of fruit free from codling moth, 

 as compared with 96.7 per cent sound fruit from four applications^ 

 In these tests the unsprayed trees showed 65.9 per cent only of sound 

 fruit. 



Dr. Felt's very valuable data obtained in New York State (Journ. 

 Econ. Ent., Vol. V, p. 153, 1912), and covering three years of experi- 

 mental work, shows for the entire period for plats receiving a single 

 application 97.35 per cent of sound fruit; for plats receiving three 

 applications 99.22 per cent of fruit free from worms as compared 

 with 79.05 per cent of sound fruit on unsprayed trees. 



The above data, while obtained under rather variable conditions 

 of experiment, establish beyond doubt that a single thorough appli- 

 cation of an arsenate-of-lead spray at once after the falling of the 

 petals will protect from codling-moth injury a large percentage of the 

 crop, though not quite so high a percentage as by several applications 

 designed to protect the fruit during the entire season. 



While the information as regards the plum curculio is not so full as 

 desirable, it also appears that this insect is controlled by the single 

 thorough treatment practically as well as by the usual three or four 

 applications. Thus the six orchards where data were obtained by 



